Medication Summary
In adults with Rocky Mountain spotted fever (RMSF), the drug of choice is doxycycline for life-threatening RMSF. Chloramphenicol is an alternative, although doxycycline is preferable because tetracyclines have been shown to be associated with a higher survival rate than chloramphenicol. [20] In vitro and in ovo R rickettsii are also susceptible to rifampin.
Doxycycline therapy also treats Lyme disease, ehrlichiosis, and relapsing fever—entities often clinically confused with RMSF. [21] Oral formulations may be used for patients being treated at home or for hospitalized patients who can take oral medications.
The American Academy of Pediatrics recommends doxycycline as the preferred treatment for children of any age with RMSF because of the potential for severe or fatal cases.
Short courses of doxycycline to treat RMSF do not cause significant dental staining. [22] Beta-lactam antibiotic coverage does not treat RMSF.
Antibiotics
Class Summary
Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting.
Doxycycline (Adoxa, Oraxyl , Doryx, Vibramycin)
Doxycycline is the drug of choice for Rocky Mountain spotted fever (RMSF). It inhibits protein synthesis and, consequently, bacterial growth by binding to 30S and possibly 50S ribosomal subunits of susceptible bacteria.
Chloramphenicol
Chloramphenicol is the alternative choice for RMSF in pregnant women and patients allergic to tetracyclines. It binds to 50S bacterial ribosomal subunits and inhibits bacterial growth by inhibiting protein synthesis.
Anticholinergic agents, Ophthamic
Class Summary
These agents relax any ciliary muscle spasm that can cause a deep, aching pain and photophobia. Cycloplegic agents are also mydriatics, and the practitioner should make sure that the patient does not have glaucoma. This medication could provoke an acute angle-closure attack.
Cyclopentolate 1% (AK-Pentolate, Cyclogyl, Cylate)
Cyclopentolate is the drug of choice in corneal abrasions. It blocks the muscle of the ciliary body and the sphincter muscle of the iris from responding to cholinergic stimulation, thus causing mydriasis and cycloplegia. Cyclopentolate induces mydriasis in 30-60 minutes and cycloplegia in 25-75 minutes. These effects last up to 24 hours.
Topical Corticosteroids
Class Summary
Corticosteroids suppress active disease, which is assumed to be due to inflammatory mechanisms.
Prednisolone ophthalmic (Omnipred, Pred Forte, Pred Mild)
This agent decreases autoimmune reactions, possibly by suppressing key components of the immune system.
Loteprednol etabonate (Lotemax, Alrex)
Loteprednol etabonate decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing increased capillary permeability. It is a topical ester steroid drop with decreased risk of glaucoma. Loteprednol etabonate is available in 0.2% and 0.5% drops.
Nonsteroidal Anti-Inflammatory Agents
Class Summary
These drugs have analgesic and anti-inflammatory activities. Their mechanism of action is not known, but they may inhibit cyclooxygenase activity and prostaglandin synthesis. Other mechanisms may exist as well, such as inhibition of leukotriene synthesis, lysosomal enzyme release, lipoxygenase activity, neutrophil aggregation, and various cell membrane functions.
Diclofenac ophthalmic (Voltaren Ophthalmic)
This agent inhibits prostaglandin synthesis by decreasing the activity of the enzyme cyclooxygenase, which in turn decreases formation of prostaglandin precursors. Diclofenac ophthalmic may facilitate outflow of aqueous humor and decreases vascular permeability.
Ketorolac ophthalmic (Acular, Acuvail)
Ketorolac ophthalmic is available in preserved bottles, as well as in preservative-free, single-dose-unit containers.
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The patient's rash is a major diagnostic sign of Rocky Mountain spotted fever (RMSF). Courtesy of Springer Nature [Bal AK, Kairys SW. Kawasaki disease following Rocky Mountain spotted fever: a case report. Journal of Medical Case Reports. 2009;3:7320. Available at: http://www.jmedicalcasereports.com/content/3/1/7320. Accessed July 25, 2013.]
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The patient's rash is a major diagnostic sign of Rocky Mountain spotted fever (RMSF). Courtesy of the Centers for Disease Control and Prevention (CDC).
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In the United States, the American dog tick (Dermacentor variabilis) is the most commonly identified source of transmission. This tick is actually found mainly east of the Rocky Mountains. The Rocky Mountain wood tick (Dermacentor andersoni), found predominantly in the mountain states, can transmit RMSF and tularemia to humans. The brown dog tick (Rhipicephalus sanguineus) is a source of RMSF in the southwestern United States and along the US-Mexico border, but it is found throughout the country and the world. Courtesy of the Centers for Disease Control and Prevention (CDC).
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An adult female Dermacentor variabilis (American dog tick). Courtesy of the Centers for Disease Control and Prevention (CDC) (https://www.cdc.gov/rmsf/index.html).
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Annual incidence (per million persons) of Spotted Fever Rickettsiosis (SFR) in the United States, 2018. As of January 1, 2010, cases of Rocky Mountain Spotted Fever (RMSF) have been reported under a new category called Spotted Fever Rickettsiosis (SFR). Courtesy of the Centers for Disease Control and Prevention (CDC) (https://www.cdc.gov/rmsf/stats/index.html#anchor_1531851146113).
